1. Field of the Invention
The present invention relates to a data processing apparatus capable of suppressing its self-repeat function under certain conditions.
2. Description of the Related Art
Many prior art data processing apparatuses consist of a keyboard having a large number of key switches arranged thereon, an apparatus proper for processing the input data resulting from keyboard operations, and an output device (printer, display unit, etc.) on which to output the data coming from the keyboard. Some English language word processors have a keyboard and a display unit which displays a plurality of lines. Word processors of this type operate in one of two modes: word processing editing mode or typewriter mode. In the word processing mode, input data from the keyboard is displayed on the display unit to create or edit documents, and no data is printed out. In typewriter mode, every keystroke on the keyboard results in a print operation of the corresponding character on the printer.
The keys on the keyboard comprise not only character keys but also function keys. On some models of word processors, offering a variety of functions, the number of keys available on the keyboard is not sufficient to accommodate all the functions. As a result, some keys represent more than one function. For example, the return key may be used to change lines during actual word processing and to specify execution of a selected menu item when a menu is displayed. These keys, each representing a plurality of functions and used to specify them, are called multipurpose keys.
During menu display, the display unit displays a menu of items indicative of various actions. Using cursor movement keys, an operator positions the cursor at a desired item shown on the display unit. Pushing the return key erases the menu display screen and executes the action represented by the selected item by displaying a screen, or first screen, of the processing action.
With many word processors, some of the keys on the keyboard are called self-repeat function keys. These keys, which include cursor movement keys, the space key and the return key, each execute an assigned function once when operated once and repeatedly when held down longer than a predetermined period of time (e.g., 0.5 sec.).
To illustrate, when selecting word processing/editing mode from the menu display, the operator moves and positions the cursor to the corresponding action indicator on the menu display screen and then presses the return key for execution. One disadvantage of the above self-repeat function scheme is that the operator sometimes inadvertently keeps depressing the return key after word processing/editing mode is selected. The continuous depression of the return key executes the line change routine, which is another return key function. As a result of this, the screen is scrolled. When the operator becomes aware of the undesired scrolling and releases the return key, it is necessary to move the cursor back to the first line. Thus, redundant operation, or carriage return, caused by the lengthy depression of the return key, delays the start of work in the word processing/editing mode. Similar disadvantages are also observed with other multipurpose, self-repeating keys.